Light control for belt type ice maker



Nov. 15, 1966 N. J. PANSING 3,285,029

LIGHT CONTROL FOR BELT TYPE ICE MAKER Filed March 28, 1966 INVENTQR. Ale/son J. Pansmg His Altar/ray United States Patent 3,285,029 LIGHT CONTROL FOR BELT TYPE ICE MAKER Nelson J. Pansing, Clayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Mar. 28, 1966, Ser. No. 537,767 5 Claims. (Cl. 62-135) This invention pertains to liquid freezers and more particularly to means for controlling the ejection of frozen liquid from the mold when it is frozen.

To obtain the maximum capacity of a liquid freezer, it is necessary to eject the frozen liquid as soon as it is frozen. Yet, it is undesirable to eject any partially frozen liquid before it is completely frozen.

It is an object of this invention to provide a detecting system which is very sensitive to the change from the unfrozen condition to the frozen condition of a liquid for controlling its ejection from a mold.

It is another object of this invention to provide a light detecting system sensitive to the drop in light transmission through the liquid when it changes from the unfrozen to the frozen condition for controlling the ejection from the mold.

These and other objects are attained in the form shown in the drawings in which a belt type endless mold of translucent material is mounted upon a set of sprockets, one of which has ejecting ribs for ejecting the frozen liquid from the pockets of receptacles in the belt which mold the frozen liquid. The pockets are filled from a spout at one end of the belt. According to my invention, at the opposite end of the belt a light is positioned to direct its light rays through the pockets or compartments in the belt including the liquid contained in the pockets and the transluscent wall thereof as the pockets or compartments move consecutively toward the sprocket provided with the ejecting ribs. On the opposite side of the belt in position to receive the light rays is a light sensitive resistance which, when illuminated, allows current flow through a normally closed relay which'opens to stop the driving of the belt. The current flow increases substantially uninterrupted until the liquid has substantially frozen. In the frozen condition the liquid is substantially opaque so that substantially no current will flow through the light sensitive resistance. The decrease in current flow causes the closing of the relay to drive the driving motor as long as the light rays are stopped by the opaque frozen liquid in pockets of the belt. The belt will advance at a controlled rate so that the completely frozen liquid is always present at the place where the light is shining throught he belt. The light rays will be substantially stopped as long as the completely frozen liquid is present and the light dependent resistance will have a resistance value. When incompletely frozen liquid advances to the light, the light dependent resistance is illuminated, its resistance is very low so that current will flow through its circuit to energize a relay which opens a switch to the belt driving motor. This slows down or stops the belt to allow more time for freezing. The belt will not resume operation until the pockets of the belt passing into the path of the light rays present the opaque frozen liquid to stop the operation thereof.

Further objects and advantages of the present invention will be apparent from the following description, reference being bad to the accompanying drawings wherein preferred embodiments of the present invention are clearly shown.

In the drawings:

FIGURE 1 is a diagrammatic perspective of an ice maker embodying one form of my invention together with a refrigerating system therefor:

FIGURE 2 is a wire diagram of FIGURE 1.

3,285,029 Patented Nov. 15, 1966 "ice Referring now to FIGURE 1, there is shown in a freezing compartment 19 a 'belt type freezer comprising an endless belt 20 having transverse rows of compartments 22. The opposite ends of the belt 20 are supported upon the sprockets 24 and 26. The front sprocket is provided with ejecting ribs 28 between the projections 30 which engage the belt between the compartments 22. The axially extending ribs 28 between the projections 30 engage the bottom walls of the compartments 22 to eject the frozen liquid from the compartments 22 as they pass around the sprocket 30.

The sprocket 30 is driven through gearing by an electric drive motor 36 which rotates the sprocket 30 at a speed faster than the normal operation. A water supply conduit 38 at the opposite end of the belt is controlled by an electrically operated valve 40 which, through a double throw switch 133 is operated by the belt to open the valve 40 whenever a row of compartments 22 passes it directly below the spout 38. The liquid to be frozen in the compartrnents 22 of the belt 20 is cooled by air circulation established by the fan 101 which draws air through the evaporating means 103 and discharges the air through the interior of the belt 20 and around the sprockets 24, 26 having the ribs 28 pressing against the bottoms of the compartments 105 to eject the frozen liquid therefrom. The evaporator 103 is supplied with liquid refrigerant from a motor compressor unit 104 which pumps the refrigerant into a condenser 107 from which the liquid refrigerant is discharged through the valve 109 back to the evaporator 103. The operation of the 'belt continues as long as liquid of the type used for freezing comestibles reaches the frozen state at the detector station. At the detector station, a light 111 directs light rays through the compartments 113 along one edge consecutively on to the light dependent resistance 115. Since the belt 20 is translucent the light rays will pass through the clear unfrozen liquid in the compartment 113 and the walls thereof on to the light dependent resistance 115, but the light rays will be reflected when the liquid is frozen. As long as the liquid in the compartment beneath the light 111 is frozen and reflects the light, the light dependent resistance 115 will have a high resistance to allow the relay contacts to close to energize the drive motor 36 so that the belt 20 will operate. However, almost instantaneously, when clear unfrozen liquid reaches the path of the light rays, the driving motor 36 will be stopped until the liquid in the compartment 113 beneath the light-111 is frozen.

In FIGURE 2 a wiring diagram is shown which includes the light dependent resistance 115. This light dependent resistance 115 is connected in series with a bin switch 117 as Well as a diode rectifier 119, a variable calibrating resistance 121 and the coil 123 of the relay. The opposite ends of this circuit are connected to the supply conductors L-1 and L-2. The relay coil 123 when energized opens the switch 125 connected in series with the conductors 127, 129, 131 and the belt drive motor 36 across the supply conductors L-1 and L-2. The conductor 129 is also connected through the double throw liquid fill'control switch 133 with the control system for the liquid fill valve 40. The opposite terminals of the double throw switch 133 are connected by the conductors 135 and 137 to the opposite terminals of a cam operated double throw switch 139. The operating cam 141 of the switch 139 is driven by a timer motor 143 which is connected in parallel with the solenoid operated coil 145 which opens the valve 40 when energized. This parallel circuit is connected in series with the cam operated double throw switch 139 and with the conductor 147 connecting with the supply conductor L-l. When these switches are in the position shown, the solenoid coil 145 and the timer motor 143 are energized to open the valve 40 to deliver an amount of liquid to one of the rows of the belt 20 sufficiently to substantially fill the compartments thereof. Du-ring this filling the timer motor 143 slowly rotates the cam which at a certain point when the filling is complete, moves the switch 139 to the opposite position to break the supply circuit. When the switch 133 is operated by the belt 20 to the opposite position, the timer motor 143 and the valve 40 are again energized to open the valve 40 to allow a flow of liquid to be frozen through the nozzle 38 into one of the compartments 105 beneath until the timer motor 143 again moves the switch 139 to the opposite position.

The circuit also shows the sealed motor compressor unit 104 and the fan motor 149 which drives the air circulating fan 101. These are connected in parallel across the supply conductors with a switch 151 being provided in series with the fan motor which may be open during the defrosting of the evaporator 103. Also, connected across the supply conductors is the illuminated lamp 111. The motor compressor unit 104, the fan motor 149 and the illuminating light 111, normally operates continuously to provide the forced circulation of cold air around the belt 20 for freezing the liquid in the compartments 22 of the belt 20. As long as the light from the light 111 is reflected by the frozen liquid to prevent transmission to the light dependent resistance 115, the relay coil 123 will be deenergized continuously to close the switch 125. This will keep energized the belt motor 36 and theliquid fill system to supply the liquid to be frozen and to eject the frozen liquid from the compartments 22 as they pass around the sprocket 24. The belt 20 will continue to operate at a rate which may be faster than the liquid in the compartments 22 can be frozen, until unfrozen liquid in the compartments 22 reaches the light 111 from which the light rays are transmitted through the belt 20 to the light dependent resistance 115. Its resistance will thereby be lowered sufiiciently to increase current flow through the relay coil 123 to cause it to pick up and open its switch 125 to deenergize the drive motor 36 until the liquid in the compartment 113 beneath the light 111 is frozen.

With this type of system, should the movement of the belt 20 be stopped for a substantial period of time by the filling of the bin 118 and the opening of this 'bin switch 117, the liquid in the filled compartments 22 will continue to freeze and may become completely frozen. Upon emptying the bin 118 and returning it to position, the belt 20 can operate at its maximum speed to deliver all of the completely frozen liquid in the compartments 22 to the bin 118 to augment the supply of frozen liquid available.

While the embodiments of the present invention as herein disclosed constitute preferred forms, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. A liquid freezer including a translucent mold adapted to receive a liquid to be frozen, means for supplying the -iquid to be frozen to said mold, means for freezing the liquid in said mold, means for ejecting the frozen liquid from said mold, means for directing light rays through said mold and said liquid, and light sensing means responsive to the difference in light transmission between the unfrozen and the frozen liquid for controlling the operation of said ejecting means.

2. A liquid freezer as defined in claim 1 in which the mold is in the form of an endless belt and the ejecting means comprises belt supporting sprockets and the means for driving the sprockets and the belt.

3. A liquid freezer as defined in claim 1 in which the light sensing means comprises electrical circuit means having a light dependent resistance and a switch therein.

4. A liquid freezer as defined in claim 1 in which the light sensing means comprises electrical circuit means having a. light dependent resistance and an electrical operating means, a switch means operated 'by said electrical operating means, and the ejecting means being connected in electrical series circuit relation with said switch means.

5. A liquid freezer as defined in claim 1 in which the light sensing means comprises electrical circuit means having a light dependent resistance and an electrical operating means, a switch means operated by said electrical operating means, and the ejecting means comprising belt supporting sprockets and electrical driving means for the sprockets and the belt connected in electrical series circuit relation with said switch means.

References Cited by the Examiner UNITED STATES PATENTS 3,120,108 2/1964 Pansing 3,199,309v 8/1965 Bru'baker 

1. A LIQUID FREEZER INCLUDING A TRANSCULENT MOLD ADAPTED TO RECEIVE A LIQUID TO BE FROZEN, MEANS FOR SUPPLYING THE LIQUID TO BE FROZEN TO SAID MOLD, MEANS FOR FREEZING THE LIQUID IN SAID MOLD, MEANS FOR EJECTING THE FROZEN LIQUID FROM SAID MOLD, MEANS FOR DIRECTING LIGHT RAYS THROUGH SAID MOLD AND SAID LIQUID, AND LIGHT SENSING MEANS RESPONSIVE TO THE DIFFERENCE IN LIGHT TRANSMISSION BETWEEN THE UNFROZEN AND THE FROZEN LIQUID FOR CONTROLLING THE OPERATION OF SAID EJECTING MEANS. 